10.1 was released in 2014 and reached EOL in 2016. The screenshot appears to show a 10.1-p45 kernel that was built from December 2016 sources in September 2019, at a time when the latest release was 11.3. However, the Subversion revision number in the screenshot (r272678M) does not match any point on the stable/10 or releng/10.1 branches. To get that uname line, assuming neither the version string nor the screenshot have been manipulated, you'd have to have checked out the head (development) branch from Subversion, synced it to r272678¹ (11.0-CURRENT, October 2014), then replaced some or all of the tree (but not the Subversion metadata) with the tip of the releng/10.1 branch before building and installing a kernel in 2019.
¹ https://cgit.freebsd.org/src/commit/?id=e15d3f3c0978fad0ebbc...